1. Field of the Invention
The present invention relates to a sheet feeder and a sheet feeding method, for plate-shaped members such as printing plates, which are taken out one-by-one from a state in which plate-shaped members and interleaf papers for protecting printing surfaces of the plate-shaped members are alternately stacked with one another.
2. Description of the Related Art
A technique has been developed, wherein a printing plate such as a photopolymer plate having a photosensitive layer (for example, a photopolymerization layer) provided on a support is used and an image is directly recorded on the photosensitive layer (photopolymerization layer) of the printing plate by a laser beam or the like (an automatic exposure apparatus for printing plates). In such a technique, an image can be rapidly recorded on the printing plate.
In the automatic exposure apparatus for printing plates for image recording on printing plates, a magazine accommodates a large number of printing plates in a stack, and the printing plates are removed from the magazine one-by-one and transferred to an exposure section.
There are cases in which the printing plates may be stacked with interleaf papers interposed therebetween so as to protect the printing surfaces of the plates. Due to the printing plates and the interleaf papers being alternately stacked with one another, scratch or the like of the light-sensitive layer and the support for a printing plate adjacent thereto, contacting each other, is substantially prevented.
On the other hand, in a sheet feeder, the uppermost printing plate within the magazine is taken out one-by-one with a sucker (suction cup). In the sheet feeder at this time, first the interleaf paper which covers the uppermost printing plate is taken out by suction. Thereafter, the uppermost printing plate is sucked to the sucker and removed from the magazine.
However, in this arrangement in which interleaf papers and printing plates are alternately stacked, an interleaf paper and a printing plate adjacent thereto can stick together. Therefore, there is a disadvantage in that when the interleaf paper is adhered to a sucker, a printing plate disposed immediately below the interleaf paper is lifted up together with the interleaf paper.